How to set averaged normals In Blender?
Averaged normals is called smooth shading within Blender.  The easiest way is to set an entire object as smooth or faceted by selecting a mesh object, and in Object Mode, click Smooth in the Tool Shelf. This button does not stay pressed; it forces the assignment of the “smoothing” attribute to each face in the mesh, including when you add or delete geometry.

You can save this information in your export by ensuring the option to include normals is checked.